<html>
  <head>
      <meta charset="utf-8"/>
      <style type="text/css">
        div.container{width:90%;height: 80%; background-color:gray}
        div.leftframe {background-color:#00ff99; height:200px; width:20%; float:left;}
        div.rightframe {background-color:#88BB99; height:200px; 
        width:50%;float:left;padding:50px;margin:10px}
      </style>
  </head>

<body>
<div class="container">

<div class="leftframe">
<ul>
<li>班级列表</li>
<li>学生查询</li>
<li>成绩统计</li>
<li>学校信息</li>
</ul>
</div>

<div class="rightframe"> 页面主体内容 </div>

</div>
</body>
</html>
